Subject: fix ip6_frag ctl From: Daniel Lezcano Alexey Dobriyan reported an oops when unsharing the network indefinitely inside a loop. This is because the ip6_frag is not per namespace while the ctls are. That happens at the fragment timer expiration: inet_frag_secret_rebuild function is called and this one restarts the timer using the value stored inside the sysctl field. "mod_timer(&f->secret_timer, now + f->ctl->secret_interval);" When the network is unshared, ip6_frag.ctl is initialized with the new sysctl instances, but ip6_frag has only one instance. A race in this case will appear because f->ctl can be modified during the read access in the timer callback. Until the ip6_frag is not per namespace, I discard the assignation to the ctl field of ip6_frags in ip6_frag_sysctl_init when the network namespace is not the init net. Signed-off-by: Daniel Lezcano --- net/ipv6/reassembly.c | 3 +++ 1 file changed, 3 insertions(+) Index: net-2.6.25-misc/net/ipv6/reassembly.c =================================================================== --- net-2.6.25-misc.orig/net/ipv6/reassembly.c +++ net-2.6.25-misc/net/ipv6/reassembly.c @@ -627,6 +627,9 @@ static struct inet6_protocol frag_protoc void ipv6_frag_sysctl_init(struct net *net) { + if (net != &init_net) + return; + ip6_frags.ctl = &net->ipv6.sysctl.frags; }